Figure 1: Task design and timeline.

The task was composed of four phases: The Acute Descriptive phase, in which participants chose which of three suggested sentences best described a cartoon, without receiving any feedback. The Acute Captions Phase, in which participants chose, for each cartoon, which of three suggested humoristic captions won the New Yorker Caption Contest. In this phase, after 14 of their 18 selections, participants saw a screen indicating that they were correct and that they responded faster than average. Following completion of this phase, participants saw a short pre-recorded video in which an actor that presents himself as the director of research is attributing participants’ excellent performance in the caption task to their evidently high levels of emotional intelligence and sense of humour (Supplementary Movie 1). Next, the Sustained Descriptive Phase and Sustained Captions Phase were presented, which are identical to the Acute Descriptive and Captions phases, respectively, with the exception that no feedback was given to participants at any point. In addition, three resting state scans were acquired (before the acute phase (rest 1); following the acute phase (rest 2); and following the sustained phase (rest 3)) to investigate the neural basis of spontaneous affect fluctuations in the absence of external stimuli. Finally, participants were asked to rate their current mood state at six time points throughout the task via a visual analogue mood scale (VAMS).